.\" $OpenBSD: X509_cmp.3,v 1.1 2019/08/20 13:27:19 schwarze Exp $
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.Dd $Mdocdate: August 20 2019 $
.Dt X509_CMP 3
.Os
.Sh NAME
.Nm X509_cmp ,
.Nm X509_NAME_cmp ,
.Nm X509_issuer_and_serial_cmp ,
.Nm X509_issuer_name_cmp ,
.Nm X509_subject_name_cmp ,
.Nm X509_CRL_cmp ,
.Nm X509_CRL_match
.Nd compare X.509 certificates and related values
.Sh SYNOPSIS
.In openssl/x509.h
.Ft int
.Fo X509_cmp
.Fa "const X509 *a"
.Fa "const X509 *b"
.Fc
.Ft int
.Fo X509_NAME_cmp
.Fa "const X509_NAME *a"
.Fa "const X509_NAME *b"
.Fc
.Ft int
.Fo X509_issuer_and_serial_cmp
.Fa "const X509 *a"
.Fa "const X509 *b"
.Fc
.Ft int
.Fo X509_issuer_name_cmp
.Fa "const X509 *a"
.Fa "const X509 *b"
.Fc
.Ft int
.Fo X509_subject_name_cmp
.Fa "const X509 *a"
.Fa "const X509 *b"
.Fc
.Ft int
.Fo X509_CRL_cmp
.Fa "const X509_CRL *a"
.Fa "const X509_CRL *b"
.Fc
.Ft int
.Fo X509_CRL_match
.Fa "const X509_CRL *a"
.Fa "const X509_CRL *b"
.Fc
.Sh DESCRIPTION
.Fn X509_cmp
compares two X.509 certificates using
.Xr memcmp 3
on the SHA1 hashes of their canonical (DER) representations as generated with
.Xr X509_digest 3 .
.Pp
.Fn X509_NAME_cmp
compares two X.501
.Vt Name
objects using their canonical (DER) representations generated with
.Xr i2d_X509_NAME 3 .
.Pp
.Fn X509_issuer_and_serial_cmp
compares the
.Fa issuer
and
.Fa serialNumber
fields of two
.Vt TBSCertificate
structures, using
.Fn X509_NAME_cmp
for the
.Fa issuer
fields.
.Pp
.Fn X509_issuer_name_cmp
compares the
.Fa issuer
fields of two
.Vt TBSCertificate
structures using
.Fn X509_NAME_cmp .
.Pp
.Fn X509_subject_name_cmp
compares the
.Fa subject
fields of two
.Vt TBSCertificate
structures using
.Fn X509_NAME_cmp .
.Pp
.Fn X509_CRL_cmp
is misnamed; it only compares the
.Fa issuer
fields of two
.Vt TBSCertList
structures using
.Fn X509_NAME_cmp .
.Pp
.Fn X509_CRL_match
compares two certificate revocation lists using
.Xr memcmp 3
on the SHA1 hashes of their canonical (DER) representations as generated with
.Xr X509_CRL_digest 3 .
.Sh RETURN VALUES
All these functions return 0 to indicate a match or a non-zero value
to indicate a mismatch.
.Pp
.Fn X509_NAME_cmp ,
.Fn X509_issuer_and_serial_cmp ,
.Fn X509_issuer_name_cmp ,
.Fn X509_subject_name_cmp
and
.Fn X509_CRL_cmp
may return -2 to indicate an error.
.Sh SEE ALSO
.Xr i2d_X509_NAME 3 ,
.Xr X509_CRL_new 3 ,
.Xr X509_digest 3 ,
.Xr X509_NAME_new 3 ,
.Xr X509_new 3
.Sh STANDARDS
RFC 5280: Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile
.Bl -dash -compact -offset indent
.It
section 4.1: Basic Certificate Fields
.It
section 5.1: CRL Fields
.El
.Sh HISTORY
.Fn X509_issuer_and_serial_cmp ,
.Fn X509_issuer_name_cmp ,
and
.Fn X509_subject_name_cmp
first appeared in SSLeay 0.5.1 and
.Fn X509_NAME_cmp
and
.Fn X509_CRL_cmp
in SSLeay 0.8.0.
These functions have been available since
.Ox 2.4 .
.Pp
.Fn X509_cmp
first appeared in OpenSSL 0.9.5 and has been available since
.Ox 2.7 .
.Pp
.Fn X509_CRL_match
first appeared in OpenSSL 1.0.0 and has been available since
.Ox 4.9 .
.Sh BUGS
For
.Fn X509_NAME_cmp ,
.Fn X509_issuer_and_serial_cmp ,
.Fn X509_issuer_name_cmp ,
.Fn X509_subject_name_cmp
and
.Fn X509_CRL_cmp ,
the return value -2 sometimes indicates a mismatch and sometimes an error.
